I ordered 2 MPX5010DP last night. (freebies!!)I think I am going to try the Dataq DI-194rs. What kind of Decoupling capacitor do I need? This does not seem to complicated, but I'm not a electrical engineer. My bro said he can wright a program in visual basics to make this work. I think I will keep my water gauges until this deal proves it self. I also seen on the Dataq site that I can have a real time display in excel if I want. The software is $99. This could get interesting.
Any other advice?
I did not mean to Hijack your thread.
It seems I have a problem with that lately.
Nick
KISS Pitot bench design
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by 86rocco » Thu Dec 22, 2005 3:23 pm
Nick, sounds like it's starting to come together, good stuff! I'm really looking forward to seeing how this turns out for you, as I'll be doing something quite similar once I get my bench up and running, be sure to let us know how it goes. As for the decoupling caps, check the app notes and data sheets on the Freescale website, they've got some example of the sensors in use, just copy what they've done.
BTW, I'm going to do like Bill's doing and make some water manometers too, I like the idea of some redunancy and having something to check my electronics against.
BTW, I'm going to do like Bill's doing and make some water manometers too, I like the idea of some redunancy and having something to check my electronics against.
- 86rocco
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by Nick » Fri Dec 23, 2005 2:02 am
I have read on the freescale site till my head hurt. I think I understand what Decoupling caps are used for, however there seems to be no consensus as to how or what value to use. And I'm not completely convinced that I need one. This electronics stuff is way complicated for my bus driver brain. This makes building a flow bench look like playing with link-logs. As for resolution that is another can of worms. In the lower ranges It would be nice to have it as accurate as in the higher ranges, but with The setup I'm building I'm not sure how the resolution is going to work out. The difference between 13% and 14% is only .01" rise. If I understand this right, this sensor should have that resolution.
Most of what is posted on this site says we should test in the 60% and up range, however I am having the same results using one large orifice and going all the way down as low as 13%.
Also, should we not be using compensated sensors for this deal? I suppose if you zero the values in your program before you test and test at room temp all the time It should be OK.
This is definitely a learning experience. I'm just glad that this is not a money sucking one, well not yet anyways.
The FP1 looks better every day.
Nick
P.S. I'm not giving up yet, The Dataq is on the way.
Most of what is posted on this site says we should test in the 60% and up range, however I am having the same results using one large orifice and going all the way down as low as 13%.
Also, should we not be using compensated sensors for this deal? I suppose if you zero the values in your program before you test and test at room temp all the time It should be OK.
This is definitely a learning experience. I'm just glad that this is not a money sucking one, well not yet anyways.
The FP1 looks better every day.
Nick
P.S. I'm not giving up yet, The Dataq is on the way.
- Nick
- Posts: 144
- Joined: Thu Oct 13, 2005 9:27 pm
- Location: Yakima WA
by 86rocco » Fri Dec 23, 2005 11:43 am
On a somewhat related note, this discussion motivated me to actual DO something yesterday, I threw together a very crude digital manometer of sorts. It uses a + 5.0 WC Setra 264 pressure transducer and it's just hooked up to a 9v battery and a digital voltmeter.The results it gives are of course in volts so a little arithmetic is needed to get meaningful numbers. I actually put this together so that I could use one of my pitot tubes to measure the air speed in my heating ducts at home, I tried it out this morning, seems to work okay.
In case anyone curious as to what kind of arithmetic's involved with this, for my pitot tubes, I subtract 2.5 from my voltage reading, take the square root of that number and multiply by 29 to get airspeed in m/sec.To be completely accurate there would also have to be correction factors for barometer pressure and temperature, I've got a spreadsheet for that but for this simple application,I'm not that picky, I just used standard pressure corrected for my altitude and normal room temperature to come up with a formula that's easy on a simple handheld calculator.
In case anyone curious as to what kind of arithmetic's involved with this, for my pitot tubes, I subtract 2.5 from my voltage reading, take the square root of that number and multiply by 29 to get airspeed in m/sec.To be completely accurate there would also have to be correction factors for barometer pressure and temperature, I've got a spreadsheet for that but for this simple application,I'm not that picky, I just used standard pressure corrected for my altitude and normal room temperature to come up with a formula that's easy on a simple handheld calculator.
- 86rocco
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by Nick » Sat Dec 24, 2005 1:53 am
Thanks, I'm beginning to get the hang of this. Well the lowest I would like to be accurate is 50%. The difference between 50% and 50.5% is .06.
This is good enough for the vertical scale. I will try it out and see how it does for the incline.
I guess if It does not do what I want then I'll order the other sensor and build the amplifier circuit.
Thanks for the help.
Nick
This is good enough for the vertical scale. I will try it out and see how it does for the incline.
I guess if It does not do what I want then I'll order the other sensor and build the amplifier circuit.
Thanks for the help.
Nick
- Nick
- Posts: 144
- Joined: Thu Oct 13, 2005 9:27 pm
- Location: Yakima WA
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